Re: [PATCH v2 2/2] iio: light: Add support for ADUX1020 sensor

[Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>]

Hi Jonathan,

Thanks for the review!

On Tue, Oct 08, 2019 at 01:27:44PM +0100, Jonathan Cameron wrote:
> On Mon, 7 Oct 2019 21:09:17 +0530
> Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org> wrote:
> 
> > Add initial support for Analog Devices ADUX1020 Photometric sensor.
> > Only proximity mode has been enabled for now.
> > 
> > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> 
> Hi Manivannan,
> 
> Various minor comments inline.
> 
> Thanks,
> 
> Jonathan
> 
> > ---
> >  drivers/iio/light/Kconfig    |  11 +
> >  drivers/iio/light/Makefile   |   1 +
> >  drivers/iio/light/adux1020.c | 783 +++++++++++++++++++++++++++++++++++
> >  3 files changed, 795 insertions(+)
> >  create mode 100644 drivers/iio/light/adux1020.c
> > 
> > diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
> > index 08d7e1ef2186..3f8c8689cd89 100644
> > --- a/drivers/iio/light/Kconfig
> > +++ b/drivers/iio/light/Kconfig
> > @@ -32,6 +32,17 @@ config ADJD_S311
> >  	  This driver can also be built as a module.  If so, the module
> >  	  will be called adjd_s311.
> >  
> > +config ADUX1020
> > +	tristate "ADUX1020 photometric sensor"
> > +	select REGMAP_I2C
> > +	depends on I2C
> > +	help
> > +	 Say Y here if you want to build a driver for the Analog Devices
> > +	 ADUX1020 photometric sensor.
> > +
> > +	 To compile this driver as a module, choose M here: the
> > +	 module will be called adux1020.
> > +
> >  config AL3320A
> >  	tristate "AL3320A ambient light sensor"
> >  	depends on I2C
> > diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
> > index 00d1f9b98f39..5d650ce46a40 100644
> > --- a/drivers/iio/light/Makefile
> > +++ b/drivers/iio/light/Makefile
> > @@ -6,6 +6,7 @@
> >  # When adding new entries keep the list in alphabetical order
> >  obj-$(CONFIG_ACPI_ALS)		+= acpi-als.o
> >  obj-$(CONFIG_ADJD_S311)		+= adjd_s311.o
> > +obj-$(CONFIG_ADUX1020)		+= adux1020.o
> >  obj-$(CONFIG_AL3320A)		+= al3320a.o
> >  obj-$(CONFIG_APDS9300)		+= apds9300.o
> >  obj-$(CONFIG_APDS9960)		+= apds9960.o
> > diff --git a/drivers/iio/light/adux1020.c b/drivers/iio/light/adux1020.c
> > new file mode 100644
> > index 000000000000..d0b76e5b44f1
> > --- /dev/null
> > +++ b/drivers/iio/light/adux1020.c
> > @@ -0,0 +1,783 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * adux1020.c - Support for Analog Devices ADUX1020 photometric sensor
> > + *
> > + * Copyright (C) 2019 Linaro Ltd.
> > + * Author: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> > + *
> > + * TODO: Triggered buffer support
> > + */
> > +
> > +#include <linux/delay.h>
> > +#include <linux/err.h>
> > +#include <linux/i2c.h>
> > +#include <linux/init.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/irq.h>
> > +#include <linux/module.h>
> > +#include <linux/mutex.h>
> > +#include <linux/regmap.h>
> > +
> > +#include <linux/iio/iio.h>
> > +#include <linux/iio/sysfs.h>
> > +#include <linux/iio/events.h>
> > +
> > +#define ADUX1020_REGMAP_NAME		"adux1020_regmap"
> > +#define ADUX1020_DRV_NAME		"adux1020"
> > +
> > +/* System registers */
> > +#define ADUX1020_REG_CHIP_ID		0x08
> > +#define ADUX1020_REG_SLAVE_ADDRESS	0x09
> > +
> > +#define ADUX1020_REG_SW_RESET		0x0f
> > +#define ADUX1020_REG_INT_ENABLE		0x1c
> > +#define ADUX1020_REG_INT_POLARITY	0x1d
> > +#define ADUX1020_REG_PROX_TH_ON1	0x2a
> > +#define ADUX1020_REG_PROX_TH_OFF1	0x2b
> > +#define	ADUX1020_REG_PROX_TYPE		0x2f
> > +#define	ADUX1020_REG_TEST_MODES_3	0x32
> > +#define	ADUX1020_REG_FORCE_MODE		0x33
> > +#define	ADUX1020_REG_FREQUENCY		0x40
> > +#define ADUX1020_REG_LED_CURRENT	0x41
> > +#define	ADUX1020_REG_OP_MODE		0x45
> > +#define	ADUX1020_REG_INT_MASK		0x48
> > +#define	ADUX1020_REG_INT_STATUS		0x49
> > +#define	ADUX1020_REG_DATA_BUFFER	0x60
> > +
> > +/* Chip ID bits */
> > +#define ADUX1020_CHIP_ID_MASK		GENMASK(11, 0)
> > +#define ADUX1020_CHIP_ID		0x03fc
> > +
> > +#define ADUX1020_MODE_OUT_SHIFT		4
> > +#define ADUX1020_MODE_OUT_PROX_I	1
> > +#define ADUX1020_MODE_OUT_PROX_XY	3
> > +
> > +#define ADUX1020_SW_RESET		BIT(1)
> > +#define ADUX1020_FIFO_FLUSH		BIT(15)
> > +#define ADUX1020_OP_MODE_MASK		GENMASK(3, 0)
> > +#define ADUX1020_DATA_OUT_MODE_MASK	GENMASK(7, 4)
> > +
> > +#define ADUX1020_MODE_INT_MASK		GENMASK(7, 0)
> > +#define ADUX1020_INT_ENABLE		0x2096
> > +#define ADUX1020_INT_DISABLE		0x2090
> > +#define ADUX1020_PROX_INT_ENABLE	0x00f0
> > +#define ADUX1020_PROX_ON1_INT		BIT(0)
> > +#define ADUX1020_PROX_OFF1_INT		BIT(1)
> > +#define ADUX1020_FIFO_INT_ENABLE	0x7f
> > +#define ADUX1020_MODE_INT_DISABLE	0xff
> > +#define ADUX1020_MODE_INT_STATUS_MASK	GENMASK(7, 0)
> > +#define ADUX1020_FIFO_STATUS_MASK	GENMASK(15, 8)
> > +#define ADUX1020_PROX_TYPE		BIT(15)
> > +
> > +#define ADUX1020_INT_PROX_ON1		BIT(0)
> > +#define ADUX1020_INT_PROX_OFF1		BIT(1)
> > +
> > +#define	ADUX1020_FORCE_CLOCK_ON		0x0f4f
> > +#define	ADUX1020_FORCE_CLOCK_RESET	0x0040
> > +#define ADUX1020_ACTIVE_4_STATE		0x0008
> > +
> > +#define ADUX1020_PROX_FREQ_MASK		GENMASK(7, 4)
> > +#define ADUX1020_PROX_FREQ_SHIFT	4
> > +
> > +#define ADUX1020_LED_CURRENT_MASK	GENMASK(3, 0)
> > +#define ADUX1020_LED_PIREF_EN		BIT(12)
> > +
> > +/* Operating modes */
> > +enum adux1020_op_modes {
> > +	ADUX1020_MODE_STANDBY,
> > +	ADUX1020_MODE_PROX_I,
> > +	ADUX1020_MODE_PROX_XY,
> > +	ADUX1020_MODE_GEST,
> > +	ADUX1020_MODE_SAMPLE,
> > +	ADUX1020_MODE_FORCE = 0x0e,
> > +	ADUX1020_MODE_IDLE = 0x0f,
> > +};
> > +
> > +struct adux1020_data {
> > +	struct i2c_client *client;
> > +	struct iio_dev *indio_dev;
> > +	struct mutex lock;
> > +	struct regmap *regmap;
> > +};
> > +
> > +struct adux1020_mode_data {
> > +	u8 bytes;
> > +	u8 buf_len;
> > +	u16 int_en;
> > +};
> > +
> > +static const struct adux1020_mode_data adux1020_modes[] = {
> > +	[ADUX1020_MODE_PROX_I] = {
> > +		.bytes = 2,
> > +		.buf_len = 1,
> > +		.int_en = ADUX1020_PROX_INT_ENABLE,
> > +	},
> > +};
> > +
> > +static const struct regmap_config adux1020_regmap_config = {
> > +	.name = ADUX1020_REGMAP_NAME,
> > +	.reg_bits = 8,
> > +	.val_bits = 16,
> > +	.max_register = 0x6F,
> > +	.cache_type = REGCACHE_NONE,
> > +};
> > +
> > +static const int adux1020_def_conf[][2] = {
> > +	{ 0x000c, 0x000f },
> > +	{ 0x0010, 0x1010 },
> > +	{ 0x0011, 0x004c },
> > +	{ 0x0012, 0x5f0c },
> > +	{ 0x0013, 0xada5 },
> > +	{ 0x0014, 0x0080 },
> > +	{ 0x0015, 0x0000 },
> > +	{ 0x0016, 0x0600 },
> > +	{ 0x0017, 0x0000 },
> > +	{ 0x0018, 0x2693 },
> > +	{ 0x0019, 0x0004 },
> > +	{ 0x001a, 0x4280 },
> > +	{ 0x001b, 0x0060 },
> > +	{ 0x001c, 0x2094 },
> > +	{ 0x001d, 0x0020 },
> > +	{ 0x001e, 0x0001 },
> > +	{ 0x001f, 0x0100 },
> > +	{ 0x0020, 0x0320 },
> > +	{ 0x0021, 0x0A13 },
> > +	{ 0x0022, 0x0320 },
> > +	{ 0x0023, 0x0113 },
> > +	{ 0x0024, 0x0000 },
> > +	{ 0x0025, 0x2412 },
> > +	{ 0x0026, 0x2412 },
> > +	{ 0x0027, 0x0022 },
> > +	{ 0x0028, 0x0000 },
> > +	{ 0x0029, 0x0300 },
> > +	{ 0x002a, 0x0700 },
> > +	{ 0x002b, 0x0600 },
> > +	{ 0x002c, 0x6000 },
> > +	{ 0x002d, 0x4000 },
> > +	{ 0x002e, 0x0000 },
> > +	{ 0x002f, 0x0000 },
> > +	{ 0x0030, 0x0000 },
> > +	{ 0x0031, 0x0000 },
> > +	{ 0x0032, 0x0040 },
> > +	{ 0x0033, 0x0008 },
> > +	{ 0x0034, 0xE400 },
> > +	{ 0x0038, 0x8080 },
> > +	{ 0x0039, 0x8080 },
> > +	{ 0x003a, 0x2000 },
> > +	{ 0x003b, 0x1f00 },
> > +	{ 0x003c, 0x2000 },
> > +	{ 0x003d, 0x2000 },
> > +	{ 0x003e, 0x0000 },
> > +	{ 0x0040, 0x8069 },
> > +	{ 0x0041, 0x1f2f },
> > +	{ 0x0042, 0x4000 },
> > +	{ 0x0043, 0x0000 },
> > +	{ 0x0044, 0x0008 },
> > +	{ 0x0046, 0x0000 },
> > +	{ 0x0048, 0x00ef },
> > +	{ 0x0049, 0x0000 },
> > +	{ 0x0045, 0x0000 },
> > +};
> > +
> > +static const int adux1020_rate[][2] = {
> > +	{ 0, 100000 },
> > +	{ 0, 200000 },
> > +	{ 0, 500000 },
> > +	{ 1, 0 },
> > +	{ 2, 0 },
> > +	{ 5, 0 },
> > +	{ 10, 0 },
> > +	{ 20, 0 },
> > +	{ 50, 0 },
> > +	{ 100, 0 },
> > +	{ 190, 0 },
> > +	{ 450, 0 },
> > +	{ 820, 0 },
> > +	{ 1400, 0 },
> > +};
> > +
> > +static const int adux1020_led_current[][2] = {
> > +	{ 0, 25000 },
> > +	{ 0, 40000 },
> > +	{ 0, 55000 },
> > +	{ 0, 70000 },
> > +	{ 0, 85000 },
> > +	{ 0, 100000 },
> > +	{ 0, 115000 },
> > +	{ 0, 130000 },
> > +	{ 0, 145000 },
> > +	{ 0, 160000 },
> > +	{ 0, 175000 },
> > +	{ 0, 190000 },
> > +	{ 0, 205000 },
> > +	{ 0, 220000 },
> > +	{ 0, 235000 },
> > +	{ 0, 250000 },
> > +};
> > +
> > +static void adux1020_flush_fifo(struct adux1020_data *data)
> > +{
> > +	/* Force Idle mode */
> > +	regmap_write(data->regmap, ADUX1020_REG_FORCE_MODE,
> > +		     ADUX1020_ACTIVE_4_STATE);
> > +	regmap_update_bits(data->regmap, ADUX1020_REG_OP_MODE,
> > +			   ADUX1020_OP_MODE_MASK, ADUX1020_MODE_FORCE);
> > +	regmap_update_bits(data->regmap, ADUX1020_REG_OP_MODE,
> > +			   ADUX1020_OP_MODE_MASK, ADUX1020_MODE_IDLE);
> > +
> > +	/* Flush FIFO */
> > +	regmap_write(data->regmap, ADUX1020_REG_TEST_MODES_3,
> > +		     ADUX1020_FORCE_CLOCK_ON);
> > +	regmap_write(data->regmap, ADUX1020_REG_INT_STATUS,
> > +		     ADUX1020_FIFO_FLUSH);
> > +	regmap_write(data->regmap, ADUX1020_REG_TEST_MODES_3,
> > +		     ADUX1020_FORCE_CLOCK_RESET);
> > +}
> > +
> > +static int adux1020_read_fifo(struct adux1020_data *data, u16 *buf, u8 buf_len)
> > +{
> > +	int i, ret = -EINVAL;
> > +	unsigned int regval;
> > +
> > +	/* Enable 32MHz clock */
> > +	regmap_write(data->regmap, ADUX1020_REG_TEST_MODES_3,
> > +		     ADUX1020_FORCE_CLOCK_ON);
> > +
> > +	for (i = 0; i < buf_len; i++) {
> > +		ret = regmap_read(data->regmap, ADUX1020_REG_DATA_BUFFER,
> > +				      &regval);
> > +		if (ret < 0)
> > +			goto err_out;
> > +
> > +		buf[i] = regval;
> > +	}
> > +
> > +	/* Set 32MHz clock to be controlled by internal state machine */
> > +	regmap_write(data->regmap, ADUX1020_REG_TEST_MODES_3,
> > +		     ADUX1020_FORCE_CLOCK_RESET);
> > +
> > +err_out:
> > +	return ret;
> > +}
> > +
> > +static void adux1020_set_mode(struct adux1020_data *data,
> > +			      enum adux1020_op_modes mode)
> > +{
> > +	/* Switch to standby mode before changing the mode */
> > +	regmap_write(data->regmap, ADUX1020_REG_OP_MODE, ADUX1020_MODE_STANDBY);
> > +
> > +	/* Set data out and switch to the desired mode */
> > +	if (mode == ADUX1020_MODE_PROX_I) {
> > +		regmap_update_bits(data->regmap, ADUX1020_REG_OP_MODE,
> > +			ADUX1020_DATA_OUT_MODE_MASK,
> > +			ADUX1020_MODE_OUT_PROX_I << ADUX1020_MODE_OUT_SHIFT);
> > +		regmap_update_bits(data->regmap, ADUX1020_REG_OP_MODE,
> > +			ADUX1020_OP_MODE_MASK, ADUX1020_MODE_PROX_I);
> > +	}
> > +}
> > +
> > +static int adux1020_measure(struct adux1020_data *data,
> > +			    enum adux1020_op_modes mode,
> > +			    u16 *val)
> > +{
> > +	int ret, tries = 50;
> > +	unsigned int status;
> > +
> > +	mutex_lock(&data->lock);
> > +
> > +	/* Disable INT pin as polling is going to be used */
> > +	regmap_write(data->regmap, ADUX1020_REG_INT_ENABLE,
> > +		     ADUX1020_INT_DISABLE);
> Error checking.

Yes, will add error check to regmap_ APIs wherever required.

> > +
> > +	/* Enable mode interrupt */
> > +	regmap_update_bits(data->regmap, ADUX1020_REG_INT_MASK,
> > +			   ADUX1020_MODE_INT_MASK,
> > +			   adux1020_modes[mode].int_en);
> > +
> > +	while (tries--) {
> > +		ret = regmap_read(data->regmap, ADUX1020_REG_INT_STATUS,
> > +				  &status);
> > +		if (ret < 0)
> > +			goto fail;
> > +
> > +		status &= ADUX1020_FIFO_STATUS_MASK;
> > +		if (status >= adux1020_modes[mode].bytes)
> > +			break;
> > +		msleep(20);
> > +	}
> > +
> > +	if (tries < 0) {
> > +		ret = -EIO;
> > +		goto fail;
> > +	}
> > +
> > +	ret = adux1020_read_fifo(data, val, adux1020_modes[mode].buf_len);
> > +	if (ret < 0)
> > +		goto fail;
> > +
> > +	/* Clear mode interrupt */
> > +	regmap_write(data->regmap, ADUX1020_REG_INT_STATUS,
> > +			   (~adux1020_modes[mode].int_en));
> > +	/* Disable mode interrupts */
> > +	regmap_update_bits(data->regmap, ADUX1020_REG_INT_MASK,
> > +			   ADUX1020_MODE_INT_MASK, ADUX1020_MODE_INT_DISABLE);
> > +
> > +fail:
> > +	mutex_unlock(&data->lock);
> > +
> > +	return ret;
> > +}
> > +
> > +static int adux1020_read_raw(struct iio_dev *indio_dev,
> > +			     struct iio_chan_spec const *chan,
> > +			     int *val, int *val2, long mask)
> > +{
> > +	struct adux1020_data *data = iio_priv(indio_dev);
> > +	u16 buf[3];
> > +	int ret = -EINVAL;
> > +	unsigned int regval;
> > +
> > +	switch (mask) {
> > +	case IIO_CHAN_INFO_RAW:
> > +		switch (chan->type) {
> > +		case IIO_PROXIMITY:
> > +			adux1020_set_mode(data, ADUX1020_MODE_PROX_I);
> > +			ret = adux1020_measure(data, ADUX1020_MODE_PROX_I, buf);
> > +			if (ret < 0)
> > +				return ret;
> > +
> > +			*val = buf[0];
> > +			ret = IIO_VAL_INT;
> 			return IIO_VAL_INT;
> > +			break;
> > +		default:
> 			return -EINVAL;
> > +			break;
> > +		}
> > +		break;
> > +	case IIO_CHAN_INFO_PROCESSED:
> > +		switch (chan->type) {
> > +		case IIO_CURRENT:
> > +			ret = regmap_read(data->regmap,
> > +					  ADUX1020_REG_LED_CURRENT, &regval);
> > +			if (ret < 0)
> > +				return ret;
> > +
> > +			regval = regval & ADUX1020_LED_CURRENT_MASK;
> > +
> > +			*val = adux1020_led_current[regval][0];
> > +			*val2 = adux1020_led_current[regval][1];
> > +
> > +			ret = IIO_VAL_INT_PLUS_MICRO;
> > +			break;
> > +		default:
> > +			break;
> > +		}
> > +		break;
> > +	case IIO_CHAN_INFO_SAMP_FREQ:
> > +		switch (chan->type) {
> > +		case IIO_PROXIMITY:
> > +			ret = regmap_read(data->regmap, ADUX1020_REG_FREQUENCY,
> > +					  &regval);
> > +			if (ret < 0)
> > +				return ret;
> > +
> > +			regval = (regval & ADUX1020_PROX_FREQ_MASK) >>
> > +				  ADUX1020_PROX_FREQ_SHIFT;
> > +
> > +			*val = adux1020_rate[regval][0];
> > +			*val2 = adux1020_rate[regval][1];
> > +
> > +			ret = IIO_VAL_INT_PLUS_MICRO;
> > +			break;
> > +		default:
> > +			break;
> > +		}
> > +		break;
> > +	default:
> > +		break;
> > +	}
> > +
> > +	return ret;
> > +};
> > +
> > +static int adux1020_write_raw(struct iio_dev *indio_dev,
> > +			     struct iio_chan_spec const *chan,
> > +			     int val, int val2, long mask)
> > +{
> > +	struct adux1020_data *data = iio_priv(indio_dev);
> > +	int i, ret = -EINVAL;
> > +
> > +	switch (mask) {
> > +	case IIO_CHAN_INFO_SAMP_FREQ:
> > +		if (chan->type == IIO_PROXIMITY) {
> Indent is very deep. I would suggest flipping conditions a bit.
> 
> 		if (chan->type != IIO_PROXIMITY)
> 			return -EINVAL;
> 
> 		for (i = 0; i < ARRAY_SIZE(adux1020_rate); i++) {
> 			if ((val != adux1020_rate[i][0]) ||
> 		            (val2 != adux1020_rate[i][1]))
> 				continue;
> 			return regmap_update_bits(data->regmap,
> 						  ADUX1020_REG_FREQUENCY,
> 						  ADUX1020_PROX_FREQ_MASK,
> 						  i << ADUX1020_PROX_FREQ_SHIFT);
> 
> 		}
> 		return -EINVAL;	

This code will be modified to use a helper for finding the index. Then
it will look more cleaner.

> 
> > +			for (i = 0; i < ARRAY_SIZE(adux1020_rate); i++) {
> > +				if ((val == adux1020_rate[i][0]) &&
> > +				     (val2 == adux1020_rate[i][1])) {
> > +					ret = regmap_update_bits(data->regmap,
> > +						ADUX1020_REG_FREQUENCY,
> > +						ADUX1020_PROX_FREQ_MASK,
> > +						i << ADUX1020_PROX_FREQ_SHIFT);
> > +				}
> > +			}
> > +		}
> > +		break;
> 
> direct return preferred if there is no cleanup to be done (like here).
> 
> > +	case IIO_CHAN_INFO_PROCESSED:
> > +		if (chan->type == IIO_CURRENT) {
> > +			for (i = 0; i < ARRAY_SIZE(adux1020_led_current); i++) {
> > +				if ((val == adux1020_led_current[i][0]) &&
> > +				     (val2 == adux1020_led_current[i][1])) {
> > +					ret = regmap_update_bits(data->regmap,
> > +						ADUX1020_REG_LED_CURRENT,
> > +						ADUX1020_LED_CURRENT_MASK, i);
> > +				}
> > +			}
> > +		}
> > +		break;
> > +	default:
> > +		break;
> > +	}
> > +
> > +	return ret;
> > +}
> > +
> > +static int adux1020_write_event_config(struct iio_dev *indio_dev,
> > +		const struct iio_chan_spec *chan, enum iio_event_type type,
> > +		enum iio_event_direction dir, int state)
> > +{
> > +	struct adux1020_data *data = iio_priv(indio_dev);
> > +
> > +	regmap_write(data->regmap, ADUX1020_REG_INT_ENABLE,
> > +		     ADUX1020_INT_ENABLE);
> 
> Check returns from regmap everywhere.  I've had far too many dodgy
> i2c buses in the past to assume they will always work!
> 
> > +
> > +	regmap_write(data->regmap, ADUX1020_REG_INT_POLARITY, 0);
> > +
> > +	switch (chan->type) {
> > +	case IIO_PROXIMITY:
> > +		if (dir == IIO_EV_DIR_RISING) {
> > +			regmap_update_bits(data->regmap, ADUX1020_REG_INT_MASK,
> > +					   ADUX1020_PROX_ON1_INT,
> > +					   state ? 0 : ADUX1020_PROX_ON1_INT);
> > +		} else {
> > +			regmap_update_bits(data->regmap, ADUX1020_REG_INT_MASK,
> > +					   ADUX1020_PROX_OFF1_INT,
> > +					   state ? 0 : ADUX1020_PROX_OFF1_INT);
> > +		}
> > +
> > +		/*
> > +		 * Trigger proximity interrupt when the intensity is above
> > +		 * or below threshold
> > +		 */
> > +		regmap_update_bits(data->regmap, ADUX1020_REG_PROX_TYPE,
> > +				   ADUX1020_PROX_TYPE, ADUX1020_PROX_TYPE);
> > +
> > +		/* Set proximity mode */
> > +		adux1020_set_mode(data, ADUX1020_MODE_PROX_I);
> > +		break;
> > +	default:
> > +		return -EINVAL;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static int adux1020_read_event_config(struct iio_dev *indio_dev,
> > +		const struct iio_chan_spec *chan, enum iio_event_type type,
> > +		enum iio_event_direction dir)
> > +{
> > +	struct adux1020_data *data = iio_priv(indio_dev);
> > +	int ret, mask;
> > +	unsigned int regval;
> > +
> > +	switch (chan->type) {
> > +	case IIO_PROXIMITY:
> > +		if (dir == IIO_EV_DIR_RISING)
> > +			mask = ADUX1020_PROX_ON1_INT;
> > +		else
> > +			mask = ADUX1020_PROX_OFF1_INT;
> > +		break;
> > +	default:
> > +		return -EINVAL;
> > +	}
> > +
> > +	ret = regmap_read(data->regmap, ADUX1020_REG_INT_MASK, &regval);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	return !(regval & mask);
> > +}
> > +
> > +static int adux1020_read_thresh(struct iio_dev *indio_dev,
> > +		const struct iio_chan_spec *chan, enum iio_event_type type,
> > +		enum iio_event_direction dir, enum iio_event_info info,
> > +		int *val, int *val2)
> > +{
> > +	struct adux1020_data *data = iio_priv(indio_dev);
> > +	u8 reg;
> > +	int ret;
> > +	unsigned int regval;
> > +
> > +	switch (chan->type) {
> > +	case IIO_PROXIMITY:
> > +		if (dir == IIO_EV_DIR_RISING)
> > +			reg = ADUX1020_REG_PROX_TH_ON1;
> > +		else
> > +			reg = ADUX1020_REG_PROX_TH_OFF1;
> > +		break;
> > +	default:
> > +		return -EINVAL;
> > +	}
> > +
> > +	ret = regmap_read(data->regmap, reg, &regval);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	*val = regval;
> > +
> > +	return IIO_VAL_INT;
> > +}
> > +
> > +static int adux1020_write_thresh(struct iio_dev *indio_dev,
> > +		const struct iio_chan_spec *chan, enum iio_event_type type,
> > +		enum iio_event_direction dir, enum iio_event_info info,
> > +		int val, int val2)
> > +{
> > +	struct adux1020_data *data = iio_priv(indio_dev);
> > +	u8 reg;
> > +
> > +	switch (chan->type) {
> > +	case IIO_PROXIMITY:
> > +		if (dir == IIO_EV_DIR_RISING)
> > +			reg = ADUX1020_REG_PROX_TH_ON1;
> > +		else
> > +			reg = ADUX1020_REG_PROX_TH_OFF1;
> > +		break;
> > +	default:
> > +		return -EINVAL;
> > +	}
> > +
> > +	/* Full scale threshold value is 0-65535  */
> > +	if (val < 0 || val > 65535)
> > +		return -EINVAL;
> > +
> > +	return regmap_write(data->regmap, reg, val);
> > +}
> > +
> > +static const struct iio_event_spec adux1020_proximity_event[] = {
> > +	{
> > +		.type = IIO_EV_TYPE_THRESH,
> > +		.dir = IIO_EV_DIR_RISING,
> > +		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
> > +			BIT(IIO_EV_INFO_ENABLE),
> > +	},
> > +	{
> > +		.type = IIO_EV_TYPE_THRESH,
> > +		.dir = IIO_EV_DIR_FALLING,
> > +		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
> > +			BIT(IIO_EV_INFO_ENABLE),
> > +	},
> > +};
> > +
> > +static const struct iio_chan_spec adux1020_channels[] = {
> > +	{
> > +		.type = IIO_PROXIMITY,
> > +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> > +				      BIT(IIO_CHAN_INFO_SAMP_FREQ),
> > +		.event_spec = adux1020_proximity_event,
> > +		.num_event_specs = ARRAY_SIZE(adux1020_proximity_event),
> > +	},
> > +	{
> > +		.type = IIO_CURRENT,
> > +		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
> > +		.extend_name = "led",
> 
> out channel?
> 

If I add `out channel`, the sysfs naming gets wierd (out_current_led_input).
Do you have a suggestion on how to represent it properly? This channel
is used for getting the LED driver current and the value is in mA.

> > +	},
> > +};
> > +
> > +static IIO_CONST_ATTR(sampling_frequency_available,
> > +		      "0.1 0.2 0.5 1 2 5 10 20 50 100 190 450 820 1400");
> > +
> > +static struct attribute *adux1020_attributes[] = {
> > +	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
> > +	NULL
> > +};
> > +
> > +static const struct attribute_group adux1020_attribute_group = {
> > +	.attrs = adux1020_attributes,
> > +};
> > +
> > +static const struct iio_info adux1020_info = {
> > +	.attrs = &adux1020_attribute_group,
> > +	.read_raw = adux1020_read_raw,
> > +	.write_raw = adux1020_write_raw,
> > +	.read_event_config = adux1020_read_event_config,
> > +	.write_event_config = adux1020_write_event_config,
> > +	.read_event_value = adux1020_read_thresh,
> > +	.write_event_value = adux1020_write_thresh,
> > +};
> > +
> > +static irqreturn_t adux1020_interrupt_handler(int irq, void *private)
> > +{
> > +	struct iio_dev *indio_dev = private;
> > +	struct adux1020_data *data = iio_priv(indio_dev);
> > +	int ret, status;
> > +
> > +	ret = regmap_read(data->regmap, ADUX1020_REG_INT_STATUS, &status);
> > +	if (ret < 0)
> 
> interrupt handlers have to return an irqreturn_t, so you can't just
> return random error codes.
> 

ah, yes.

> > +		return ret;
> > +
> > +	status &= ADUX1020_MODE_INT_STATUS_MASK;
> > +
> > +	if (status & ADUX1020_INT_PROX_ON1) {
> > +		iio_push_event(indio_dev,
> > +				IIO_UNMOD_EVENT_CODE(IIO_PROXIMITY, 0,
> > +					IIO_EV_TYPE_THRESH,
> > +					IIO_EV_DIR_RISING),
> > +				iio_get_time_ns(indio_dev));
> > +	}
> > +
> > +	if (status & ADUX1020_INT_PROX_OFF1) {
> > +		iio_push_event(indio_dev,
> > +				IIO_UNMOD_EVENT_CODE(IIO_PROXIMITY, 0,
> > +					IIO_EV_TYPE_THRESH,
> > +					IIO_EV_DIR_FALLING),
> > +				iio_get_time_ns(indio_dev));
> > +	}
> > +
> > +	regmap_update_bits(data->regmap, ADUX1020_REG_INT_STATUS,
> > +			   ADUX1020_MODE_INT_MASK, status);
> > +
> > +	return IRQ_HANDLED;
> > +}
> > +
> > +static int adux1020_chip_init(struct adux1020_data *data)
> > +{
> > +	struct i2c_client *client = data->client;
> > +	int ret, i;
> > +	unsigned int val;
> > +
> > +	ret = regmap_read(data->regmap, ADUX1020_REG_CHIP_ID, &val);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	val &= ADUX1020_CHIP_ID_MASK;
> > +
> > +	if (val != ADUX1020_CHIP_ID) {
> as val is only used here,
> 
> 	if (val & ADUX1020_CHIP_ID_MASK != ADUX1020_CHIP_ID) {
> 
> Saves a bit of code and isn't significantly harder to read.
> 

okay.

> > +		dev_err(&client->dev, "invalid chip id 0x%04x\n", val);
> > +		return -ENODEV;
> > +	};
> > +
> > +	dev_dbg(&client->dev, "Detected ADUX1020 with chip id: 0x%04x\n", val);
> > +
> > +	/* Perform software reset */
> 
> Try to avoid comments where the code is fairly self explanatory.
> They are just potential places to diverge from reality in the future ;)
> 

okay.

> > +	regmap_update_bits(data->regmap, ADUX1020_REG_SW_RESET,
> > +			   ADUX1020_SW_RESET, ADUX1020_SW_RESET);
> 
> This is i2c so not exactly 100% reliable (depends on good board
> design etc).  Hence I'd add error checking for all these reads and
> writes.
> 
> > +
> > +	/* Load default configuration */
> > +	for (i = 0; i < ARRAY_SIZE(adux1020_def_conf); i++)
> > +		regmap_write(data->regmap, adux1020_def_conf[i][0],
> > +			     adux1020_def_conf[i][1]);
> > +
> > +	adux1020_flush_fifo(data);
> > +
> > +	/* Use LED_IREF for proximity mode */
> > +	regmap_update_bits(data->regmap, ADUX1020_REG_LED_CURRENT,
> > +			   ADUX1020_LED_PIREF_EN, 0);
> > +
> > +	/* Mask all interrupts */
> > +	regmap_update_bits(data->regmap, ADUX1020_REG_INT_MASK,
> > +			   ADUX1020_MODE_INT_MASK, ADUX1020_MODE_INT_DISABLE);
> > +
> > +	return 0;
> > +}
> > +
> > +static int adux1020_probe(struct i2c_client *client,
> > +			  const struct i2c_device_id *id)
> > +{
> > +	struct adux1020_data *data;
> > +	struct iio_dev *indio_dev;
> > +	int ret;
> > +
> > +	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
> > +	if (!indio_dev)
> > +		return -ENOMEM;
> > +
> > +	indio_dev->dev.parent = &client->dev;
> > +	indio_dev->info = &adux1020_info;
> > +	indio_dev->name = ADUX1020_DRV_NAME;
> > +	indio_dev->channels = adux1020_channels;
> > +	indio_dev->num_channels = ARRAY_SIZE(adux1020_channels);
> > +	indio_dev->modes = INDIO_DIRECT_MODE;
> > +
> > +	data = iio_priv(indio_dev);
> > +	i2c_set_clientdata(client, indio_dev);
> > +
> > +	data->regmap = devm_regmap_init_i2c(client, &adux1020_regmap_config);
> > +	if (IS_ERR(data->regmap)) {
> > +		dev_err(&client->dev, "regmap initialization failed.\n");
> > +		return PTR_ERR(data->regmap);
> > +	}
> > +
> > +	data->client = client;
> > +	data->indio_dev = indio_dev;
> > +	mutex_init(&data->lock);
> > +
> > +	ret = adux1020_chip_init(data);
> > +	if (ret)
> 
> 		return ret;
> 
> > +		goto err_out;
> > +
> > +	if (client->irq) {
> > +		ret = devm_request_threaded_irq(&client->dev, client->irq,
> > +				NULL, adux1020_interrupt_handler,
> > +				IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
> > +				ADUX1020_DRV_NAME, indio_dev);
> > +		if (ret) {
> > +			dev_err(&client->dev, "irq request error %d\n", -ret);
> > +			goto err_out;
> 
> Direct returns are preferred in kernel code as they are generally easier
> to review.  No need to check the error handling if we immediately know
> there isn't any to be done!
> 
> 			return ret;

ack.

> > +		}
> > +	}
> > +
> > +	ret = iio_device_register(indio_dev);
> > +	if (ret) {
> > +		dev_err(&client->dev, "Failed to register IIO device\n");
> > +		goto err_out;
> 
> This error path does no error handling so you can return directly here.
> 		return ret;
> 
> But... Then there is no point in having the return here as you might
> as well drop it out of the brackets and replace the return 0 below with
> return ret;

ack.

> 
> > +	}
> > +
> > +	return 0;
> > +
> > +err_out:
> > +	return ret;
> > +}
> > +
> > +static int adux1020_remove(struct i2c_client *client)
> > +{
> > +	struct iio_dev *indio_dev = i2c_get_clientdata(client);
> > +
> > +	iio_device_unregister(indio_dev);
> If we have a remove with only iio_device_unregister it normally
> implies we could have used devm_iio_device_register and allowed
> the automatic unwinding to do it for us.
> 
> Make that change and you shouldn't need a remove function at all.
> In turn, there is no reason to then call i2c_set_clientdata()

Sure, will use devm_ API.

Thanks,
Mani

> 
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct i2c_device_id adux1020_id[] = {
> > +	{ "adux1020", 0 },
> > +	{}
> > +};
> > +MODULE_DEVICE_TABLE(i2c, adux1020_id);
> > +
> > +static const struct of_device_id adux1020_of_match[] = {
> > +	{ .compatible = "adi,adux1020" },
> > +	{ }
> > +};
> > +MODULE_DEVICE_TABLE(of, adux1020_of_match);
> > +
> > +static struct i2c_driver adux1020_driver = {
> > +	.driver = {
> > +		.name	= ADUX1020_DRV_NAME,
> > +		.of_match_table = adux1020_of_match,
> > +	},
> > +	.probe		= adux1020_probe,
> > +	.remove		= adux1020_remove,
> > +	.id_table	= adux1020_id,
> > +};
> > +module_i2c_driver(adux1020_driver);
> > +
> > +MODULE_AUTHOR("Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>");
> > +MODULE_DESCRIPTION("ADUX1020 photometric sensor");
> > +MODULE_LICENSE("GPL");
> 
>